The present invention relates generally to turf aerators and in particular provides a turf aerator which is simple to manufacture and repair.
Prior art turf aerators are known, which support a plurality of reciprocable tynes adapted to be forced into the ground at regular intervals to aerate the ground. Such prior art aerators are usually self propelled and include mechanical/hydraulic support means for the tynes, and a timing mechanism which provides a "lost motion" type movement of the tynes such that the tynes reciprocate and engage the ground in a substantially vertical plane as the machine advances. To date the available aerators have been either of very basic form, similar to a reciprocating broad fork in which the tynes extend down from a common reciprocating bar or the like and which do not give very satisfactory results, or they have been of complex form which work satisfactorily but which are difficult to service and expensive to manufacture.
In one prior art arrangement an aerator has a plurality of tynes located at the ends of tyne arms which are reciprocated by a crankshaft and arranged transversely of the aerator. The tyne arms are each slidably mounted, towards their lower end in a guide which is in turn reciprocated fore and aft to keep the tyne arm vertical while it is in engagement with the ground. The prior art tyne arms are articulated to accommodate the differing relative horizontal speeds of the crankshaft and the arm guides which maintain the lower portion of the arms in vertical orientation. Typically when an aerator is required to penetrate the ground at 50 mm spacings, the machine can only move forward 50 mm for every revolution of the crankshaft and therefore a relatively high tyne speed is required for reasonable rate of coverage. Due to their mechanical arrangement, prior art machines were subject to high rates of wear and usually required strict mechanical timing means to control the placement of tynes as the machine advanced. Further, these prior art machines are able to provide only one timing pattern with respect to forward speed and can therefore only produce one coring pattern.
Various embodiments of the present invention are designed to ameliorate the disadvantages mentioned above.